New RULE-brand Centrifugal Pump

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Wed Sep 04, 2019 8:03 pm

[To readers who have used the “new” RULE centrifugal pumps:] do you have any comments about them?

BACKSTORY: My older 800-GPH Rule centrifugal pump died—the first Rule centrifugal pump I ever had fail. The new generation [of RULE centrifugal pumps now sold] have good features like air-locks and anti-siphon. I read reviews that say that the new generation centrifugal pumps are not as good as the older ones, and they can't be run dry.

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Thu Sep 05, 2019 5:16 am

Please give a URL for the RULE website where these “new” model pumps are found.

Please give a URL to the reviews you mention that discuss the failure of the “new” models to provide the same feature for dry-running available in older models.

Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

Re: New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Thu Sep 05, 2019 9:27 pm

Here is the website for the RULE pumps. https://www.xylem.com/en-us/brands/rule/ The reviews I read on a lot of fishing/boating blogs as well as Amazon reviews.

Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

Re: New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Fri Sep 06, 2019 1:00 pm

I just received the new RULE 500 gph pump. I don't know what these reviewers were talking about. It clearly says on the package "Non burn-out when dry". Also it is submersible, ignition protected, high efficiency low-amp motor, stainless steel shaft, and includes a new back-flow preventer. These are similar features to the old models. I think that back-flow device will need to be removed and drained at winterizing time or it may trap water and freeze. The straight back-flow adapter may be a bit long for the tiny bilge sump on my fifteen footer. They offer a 90° adapter but I will have to test-fit before I decide if I need that. Otherwise the pump looks to be as good or better than prior models.

svsonora
Posts: 32
Joined: Mon Feb 04, 2019 12:18 pm

Re: New RULE-brand Centrifugal Pump

Postby svsonora » Fri Sep 06, 2019 1:32 pm

I have a rule 2000gph pump for my sailboat. The pump itself works well but their float switch is garbage. Looks like the float switch on my new-to-me whaler has failed as well (it was working when I was seeing the boat --I laugh aloud--)

Back flow probably isn't as much as a problem on the whalers, but my sailboat's bilge hose has something like 6 feet upward travel before it hits the transom drain. I installed a check valve in the line.

Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

Re: New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Fri Sep 06, 2019 2:08 pm

I have a 1990's vintage 2000gph pump that I used on my aluminum skiff. It was used as the "emergency" pump with the old style mercury float switch. That switch never failed until someone stupidly stepped on it. The replacement switch with the ball inside was useless. UPDATE: I can not find the 90° discharge fitting for the 360/500/800gph pumps. It is used on various models but does not seem to be available separately.
Last edited by Oldslowandugly on Tue Sep 10, 2019 5:59 pm, edited 1 time in total.

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Tue Sep 10, 2019 11:50 am

OLDSLOW’—thanks for giving readers your first-hand experience with a new RULE pump that contradicts what you read about them on other websites. Here on continuouswave the report of first-hand experience is much more highly valued than recitations of random “dock talk.”

Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

Re: New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Tue Sep 10, 2019 6:03 pm

Jim, I was a little suspicious of the reviews. As I said, I have never even seen a RULE pump fail before. The ability to run dry was what drew me to them in the first place.

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Sat Sep 14, 2019 7:33 am

Oldslowandugly wrote:Here is the website for the RULE pumps. https://www.xylem.com/en-us/brands/rule/


The above URL leads to to the top page of the RULE website. Are you saying that ALL the pumps that appear on this website are to be categorized as being "new" pumps that suffer the limitations attributed to them in your initial post, that is, ALL the pumps on the website are no longer as good as the "old" pumps and also cannot be run dry?

I don't see any indication on the top page that all pumps made by RULE are different now from the "old" RULE pumps.

Perhaps there really is no difference between the pumps you read about on other websites that were called "new" RULE pumps and the pumps you read about on other websites that were called "old" RULE pumps. I am just not clear at all what distinguishes "old" and "new" RULE pumps. Usually when a manufactured product is changed, there is a corresponding change in the model designator.

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Sat Sep 14, 2019 8:30 am

svsonora wrote:I have a [RULE 2000-GPH] pump for my sailboat. ...my sailboat's bilge hose has something like 6 feet upward travel before it hits the transom drain.


For an application in which a pump must lift its output more than six feet vertically, there will be a substantial reduction in the output of a centrifugal pump from its rated output. The RULE pump specification sheet shows their model 2000-GPH pump produces an output flow of 2000-GPH only when the pump output lift is zero-feet. That is a useless specification unless the pump is intended to pump water downhill. If you need to pump water uphill, that is, to lift water out of a sump area on a boat and overboard into the sea, the rating of RULE centrifugal pumps must be decreased significantly. For the 2000-GPH model, an output lift of 3.3-feet reduces the pump flow to 1,620-GPH, a derating of 380-GPH or 19-percent. An output lift of 6.6-feet reduces the pump flow to 1,300-GPH, a derating of 700-GPH or 35-percent.

A further problem with the rated flow of RULE centrifugal pumps is the operating voltage needed to produce those ratings. RULE uses an operating voltage of 13.6-Volts. The nominal terminal voltage of a fully-charged 12-Volt battery is only 12.8-Volts. RULE uses an operating voltage that is far above the voltage of a 12-Volt battery, unless the battery is being charged by a battery charger and has its terminal voltage forced to be much higher.

The model 2000-GPH 12-Volt pump is also rated to be drawing 12-Amperes at 13.6-Volts. That is 163-Watts of electrical energy. If the pump is run on 12.0-Volts, it only draws 8.4-Amperes, or 101-Watts. This represents a significant decrease in electrical power by a factor of 0.617, and there must be a corresponding significant decrease in output flow. Also note that the voltage decreased only 1.6-Volts from 13.6-Volts, a reduction of 0.88, but the electrical power consumed dropped by a factor of 0.617. This is a very non-linear reduction, more like an exponential reduction by a factor of almost 4.

A further problem is providing the electrical power to the pump. For a circuit drawing 12-Amperes, in order to reduce any electrical voltage drop in the wiring to the pump, and assuming the conductors will be at least 12-feet long, the wire gauge needed to limit the voltage drop to not more than three-percent would be 10-AWG. I suspect that there are almost NO installations of a RULE 2000 pump with the wiring to the pump done with 10-AWG conductors. This means the actual voltage at the pump is inherently going to be even lower than expected.

In summary, for a centrifugal pump that uses an unusually high voltage (13.6-Volts) as the operating voltage, uses a value of 0-feet as the amount of head on the pump output, is powered from a 12-Volt battery that is not under heavy charging current, and is connected by conductors of smaller than 10-AWG to the power source, the pump's rated output flow will never be obtained in practice.

Going back to the cited example of a 2000-GPH pump with a nominal 6.6-foot head being operated from 12-Volts at the pump (allowing for voltage drop in the conductors and a battery not under heavy charging current), the expected pump flow is going to be around 1,300-GPH (the rating for the vertical lift at 13.6-Volts) and derated of 0.617 (for the reduced electrical power) for a best-case output of about 800-GPH. That is only 40-percent of the rated pump flow volume. This reduction is clearly indicated in the manufacturer's specifications and by the physics of work and electrical power.

I suspect that some of the uncomplimentary remarks made about RULE centrifugal pumps that are read in anecdotal reports about them are due to the owner of the pump being unaware of how a centrifugal pump must be de-rated for any vertical lift on the output and how sensitive the pump is to reductions in electrical power available to operate the pump.

The mention of applications in sailboats with deep sumps is completely unrelated to use in Boston Whaler boats. In Boston Whaler boats the cockpit sump area is generally no more than a few inches below the level of the sea. Water to be lifted from the sump to the sea is generally only lifted about 1-foot or less. The de-rating of a centrifugal pump for an output for lift is shown by RULE to be linear. We can interpolate from their data that if a 3.3-foot lift reduced the flow by 0.12 the reduction is then at 0.036 per foot, and thus a lift of 1-foot would reduced flow by 0.963. A rated 2000-GPH pump would deliver 1928-GPH flow in a typical Boston Whaler boat.

For removing water from the cockpit sump of a Boston Whaler boat, the use of a RULE centrifugal pump is an excellent choice.

As for the notion that there are "old" RULE pumps that are superior to "new" rule pumps as other websites have published (somewhere unspecified in this entire discussion), I am not particularly concerned or surprised. Most websites are poorly moderated and often carry completely contradictory and unverified information. The goal of continuouswave has been to collect and organized reliable and accurate information and to debunk nonsense.

Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

Re: New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Sat Sep 14, 2019 10:03 am

I am dealing with the smaller size pumps like the 360, 500, and 800 gph models such as the average small Whaler would use. I have not investigated the many other models and cannot comment on them. I would separate the "old" and "new" lines by the new designs incorporated. The "new" pumps are able to flow max capacity at 12 volts now rather than the 13.6 volts prior. That is more in line with the average boat battery. They added air bleed holes to prevent air locking. There is an anti-back flow device added to the discharge port. That helps keep water from returning to the sump and being detected by the self-sensing models. The basket on the bottom still un-clips for cleaning. The physical shape is more modern looking but I consider that purely cosmetic and unimportant.

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Sat Sep 14, 2019 12:07 pm

Many thanks for the clarification on the new pumps.

I will look more closely at their flow ratings. Getting away from the 13.6-Volt power will be a better, more realistic rating for output.

Please give me the URL to the specification sheet of one of the "new" pumps which indicates its operation at the rated flow occurs with just 12.0-Volt power. I browsed several pump models but they had specifications sheets with 13.6-Volt flow rates.

Also, for the smaller rated pumps you mention, i.e., under 1000-GPH, the decrease in flow with vertical lift on the output is much greater as height increases. For example, a smaller pump rated at 500-GPH has its output cut in half (to 50-percent of rating) with only about a 5.5-feet lift. The 2000-GPH pump can lift 5.5-feet with only an output decrease to about 1400-GPN or 70-percent of rating. The smaller pumps seem to be disproportionally affected by vertical lift of their output.

Again, a URL that points directly to a particular pump you are talking about will be necessary to figure out what we are discussing.

Oldslowandugly
Posts: 413
Joined: Fri Jan 15, 2016 11:19 pm
Location: Queens NY

Re: New RULE-brand Centrifugal Pump

Postby Oldslowandugly » Sat Sep 14, 2019 1:17 pm

This is the RULE web site page for the 500 gph pump I bought. https://www.xylem.com/en-us/brands/rule/rule-products/500 Oddly, they did not upgrade the picture to the new design. This is the .pdf of the instruction sheet and has the better specs. https://www.xylem.com/siteassets/brand-specific-content-including-catalog/jabsco/standard-bilge-pump---technical-data-sheet---multilingual.pdf

svsonora
Posts: 32
Joined: Mon Feb 04, 2019 12:18 pm

Re: New RULE-brand Centrifugal Pump

Postby svsonora » Mon Sep 30, 2019 10:47 pm

jimh, thats exactly why I have a 2000gph pump and not something smaller (on the sailboat). I also have a backup hand operated pump rated at 28gpm. To be 100% though, I should have a second electric bilge pump. Just buying time in case I pop a through hull or get holed. Thanks for the detailed explanation on the power draw also.

My 17 SSL has a 1000 GPH pump . Both of these pumps have been run dry (on accident) for a few minutes and they are fine, as manufacturer notes.

By the way, for the OP, you can easily avoid siphoning or flow-back problems (more of a 'problem' in my sailboat) by installing a check valve. Use 2 stainless steel hose clamps, installed in opposing directions at all fittings.

Jefecinco
Posts: 1004
Joined: Fri Oct 09, 2015 6:35 pm
Location: Gulf Shores, AL

Re: New RULE-brand Centrifugal Pump

Postby Jefecinco » Tue Oct 01, 2019 9:06 am

When you say to install two hose clamps in opposing directions does that mean the screw heads should face in opposite directions? If so, what is the reasoning behind that suggestion? If not, please explain what you mean.
Butch

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Tue Oct 01, 2019 10:57 am

I think there is a misunderstanding about the so-called “new” pumps being rated for 12.00-Volts. I carefully read the installation instructions (linked above) and noted that 13.6-Volts was specified as the operating voltage.

svsonora
Posts: 32
Joined: Mon Feb 04, 2019 12:18 pm

Re: New RULE-brand Centrifugal Pump

Postby svsonora » Tue Oct 01, 2019 1:03 pm

Jefecinco wrote:When you say to install two hose clamps in opposing directions does that mean the screw heads should face in opposite directions? If so, what is the reasoning behind that suggestion? If not, please explain what you mean.


Yes, that is what I meant. But thinking about it, I don't think bilge hoses typically use double hose clamps. Below waterline fittings and some fuel lines do. AYBC requires them on fuel and exhaust. Its one of those things that 'everyone does' but here is one reason, related to pinching: https://www.boats.com/how-to/align-hose ... -properly/

Jefecinco
Posts: 1004
Joined: Fri Oct 09, 2015 6:35 pm
Location: Gulf Shores, AL

Re: New RULE-brand Centrifugal Pump

Postby Jefecinco » Wed Oct 02, 2019 9:53 am

Thanks for the explanation. I'm not sure I'm convinced but it's not a bad idea when access allows. It looks sloppy to my military mind and therefore undesirable but certainly could do no harm.
Butch

svsonora
Posts: 32
Joined: Mon Feb 04, 2019 12:18 pm

Re: New RULE-brand Centrifugal Pump

Postby svsonora » Wed Oct 02, 2019 3:58 pm

its undisputable that it is better but its disputable how much better it is. ABYC won't put out a standard without a good reason. But is it necessary in this application? I don't know. Probably not.

jimh
Posts: 7121
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: New RULE-brand Centrifugal Pump

Postby jimh » Wed Oct 02, 2019 10:31 pm

svsonora wrote:its undisputable that it is better but its disputable how much better it is. ABYC won't put out a standard without a good reason. But is it necessary in this application? I don't know. Probably not.


Too many “it” pronouns. What are you saying?